The broadcast spectrum is divided up into different frequencies and allocated among different broadcasters for various uses in different geographic regions. The frequencies of the spectrum are allocated based on licenses granted to the broadcasters. Based on the allocations, a broadcaster may be limited to broadcasting a specific type of content, such a television signal, on a certain frequency within a certain geographic radius. Broadcasting outside of an allocated spectrum could be a violation for the broadcaster.
If a broadcaster wishes to transmit another type of content within that geographic radius, the broadcaster may be required to obtain an additional spectrum license and in turn be allocated an additional frequency within that frequency. Similarly, if a broadcaster wishes to transmit content within another geographic radius, the broadcaster may be required to obtain an additional spectrum license for that region. Obtaining, additional spectrum licenses, however, may be difficult, time consuming, expensive, and impractical.
In addition, a broadcaster may not always fully utilize an entire portion of spectrum for which it has been granted a license. This may create inefficiencies in the utilization of the broadcast spectrum.
Moreover, the anticipated use of the broadcast spectrum may be changing. For example, current broadcast television solutions are monolithic and designed for a primary singular service. However, broadcasters may anticipate providing multiple wireless-based types of content, in addition to broadcast television in the future, including mobile broadcasting and IoT services. In particular, there are many scenarios where a large number of devices may all wish to receive identical data from a common source beyond broadcast television. One such example is mobile communication services, where a large number of mobile communication devices in various geographic locations may all need to receive a common broadcast signal conveying the same content, such as a software update or an emergency alert, for example. In such scenarios, it is significantly more efficient to broadcast or multicast the data to such devices rather than individually signaling the same data to each device. Thus, a hybrid solution may be desirable.
To more efficiently utilize the broadcast spectrum, different types of content may be time-multiplexed together within a single RF channel. Further, different sets of transmitted content may need to be transmitted with different encoding and transmission parameters, either simultaneously, in a time division-multiplexed fashion (TDM), in a frequency division—multiplexed (FDM), layer division-multiplexed (LDM) or a combination. The amount of content to be transmitted may vary with time and/or frequency.
In addition, content with different quality levels (e.g. high definition video, standard definition video, etc.) may need to be transmitted to different groups of devices with different propagation channel characteristics and different receiving environments. In other scenarios, it may be desirable to transmit device-specific data to a particular device, and the parameters used to encode and transmit that data may depend upon the device's location and/or propagation channel conditions.
At the same time, the demand for high-speed wireless data continues to increase, and it is desirable to make the most efficient use possible of the available wireless resources (such as a certain portion of the wireless spectrum) on a potentially time-varying basis.
Furthermore, it may be desirable for a receiver to identify and distinguish high priority communications, such as an emergency communication for example, that should be given immediate or high priority attention even when a receiver is in an Idle state. A receiver may be in one of two states, for example. In an Active state, a receiver is turned on (from the end user's perspective), and is receiving, decoding, and presenting transmitted information such as a television program or movie. At the same time that an Active state receiver is decoding a regular transmission, it can easily monitor for a high priority transmission as well. In an Idle state, a receiver is turned off from the end user's perspective but is not completely powered off. An idle receiver would not be presenting transmitted information to the end user on an ongoing basis. However, an idle receiver may still need to monitor for and identify high priority communications. For example, it may be desirable for a mobile phone to receive an emergency alert notification event while the mobile phone is turned off (although not completely powered off). If a high priority communication is identified, then an Idle receiver may be expected to process the accompanying information and then present such information to the end user.
It should be appreciated that a receiver may be a battery powered mobile device such as a tablet computer or smartphone rather than a stationary device connected to an electric grid. Switching such a device from an Idle state to an Active state may consume extra battery power. Thus, in order to conserve battery power, it may be desirable for improved efficiency to maximize a receiver's time in an idle state and minimize the receiver's time in an Active state while still effectively monitoring for and identifying high priority communications with little delay.
In one example solution, an idle receiver may be configured to inspect every transmitted communication to determine whether the communication is a high priority communication. However, such a solution may not be efficient and may not effectively conserve a receiver's battery power.